DE19536381A1 - Epoxy and epoxy polyacrylate dispersions containing reactive diluents, process for their preparation and their use - Google Patents

Abstract

Aq., low-solvent coating material, contains: (I) a base resin dispersion comprising: (A) an epoxy resin obtd. by condensation of: (A-1) 50-95 wt% epoxide(s) with at least 2 epoxide gps.; and (A-2) 5-50 wt% aromatic polyol; (B) a dispersant comprising: (B-1) a condensation prod. of: (B-11) an aliphatic polyol with a mol. wt. (Mw) of 200-20,000 g/mol; and (B-12) an epoxide cpd. with at least 2 epoxide gps.; (C) a diluent comprising: (C-1) low-mol. wt. liq. epoxy-functional cpds.; and (D) water., together with: (II) an aq. hardener for (I) which is suitable for hardening at room temp. or elevated temp. (forced drying). The amts. of components (I) and (II) are such that the ratio of the number of reactable epoxide gps. in (I) to the number of amine H atoms in (II) is (1:0.75)-(1:2.0). Also claimed are: (i) a process for the prodn. of aq. modified epoxy resin dispersions (I); (ii) aq. low-solvent coating material obtd. by this process; (iii) coatings produced with coating material; and (iv) matt clear-coat compsns. and water-dilutable adhesives contg. aq. dispersions as above.

Description

From DE-A 36 43 751 aqueous epoxy resin dispersions are already knows that in the presence of a condensation product from an aliphati rule polyol and an epoxy compound as an emulsifier. However, these aqueous dispersions always contain one in addition to water certain amount of organic solvents. In DE-A 41 28 487 A way has been described of how to use this amount of organic solution can further reduce mean while improving Properties of these dispersions. For this, the base resin is no longer in Presence of the emulsifier condenses and flexibilizing poly epoxies used as raw materials for the epoxy resin; in the examples of DE-A 41 28 487 uses polypropylene glycol diglycidyl ether.

These dispersions have a significantly reduced solvent content with improved application properties. In the course of always further striving to minimize volatile organic components in aqueous paints, however, the reduced solution proves itself medium content as problematic, in addition, to make the Ba expensive raw materials are used, which are also negative Can have an impact on the property profile.

Above all, cold-curing systems such as those for corrosion and Building protection or those that are subjected to forced drying are special from the point of view of solvent emission to be viewed critically, since here, as with stoving systems, a thermi After-burning of the solvent can take place.  

A major improvement of the existing systems would therefore be one Binder based on a completely solvent-free dispersion, which can be used in the area of cold-curing coatings.

The solvents used generally serve mainly as coalesces agents that slowly evaporate from the film after filming and thus unfavorable working conditions in terms of industrial hygiene as well as undesirable cause the emission of organic components into the atmosphere. In addition, solvent residues inevitably remain in the coating, which adversely affect their properties. Without such a solution medium, however, you get poor filming and course, what to tarnish, poorly adhering films.

That reactive thinners have a positive effect (reduction in viscosity) in con conventional epoxy resin formulations and water-thinnable liquid resins is known to the person skilled in the art. However, she is hardly described Use in solid epoxy resin dispersions. In the US-A 4,315,044, US-A 4,399,242 and US-A 4,608,406 the use of C₈-C₈₀-alkyl monoepoxides in non-ionically stabilized solid epoxy resin Dispersions described for curing at room temperature or in the heat. These reactive diluents are stirred into the finished dispersion and Improve shear stability, freeze-thaw stability, storage stability and the gloss of the coatings, but what z. T. only through the additional Use of glycols or glycol ethers can be achieved satisfactorily.

On the other hand, the function of the reactive thinners as Koa is not mentioned Lenses, especially not mention that the addition to the resin before the actual dispersion process is particularly advantageous.  

The subsequent addition of substances to a finished, non-ionic stabilized solid resin dispersion is especially designed for high solids The dispersion is very cumbersome because of the different viscous / polar Components need to be well homogenized with each other, what in size ren mixing units is unsatisfactory. It can also on this Do not show such a high degree of mixing of resin and reactive agent can be achieved thinner because these components exist in separate micelles lie.

The object of the present invention was to provide epoxy containing reactive diluents or to produce epoxy-acrylate dispersions which have no further coalescence need more and more properties compared to conventional dispersions or those with retrospectively given given reactive diluents.

Surprisingly, it has now been found that by using Reak tiv thinners using a special process, namely before dispersing process, different, always extremely low solvent or even solution medium-free epoxy resin or epoxy polyacrylate dispersions can be produced, which is very good for room temperature curing or forced drying suitable and excellent even without the addition of other coalescing agents Filming and have very good application properties.

The invention accordingly relates to aqueous, low-solvent or solvent-free coating agents that contain the following components:

• (I) A base resin dispersion consisting of
  • (A) an epoxy resin, which is a condensation product of mass fractions of
    • (A-1) 50 to 95, preferably 55 to 85% of one or more epoxy compound (s) with at least two epoxy groups per molecule and preferably an epoxy group content of 300 to 12,000 mmol / kg ("epoxy equivalent weight" = molar mass divided by number the epoxy groups per molecule from 90 to 3000 g / mol),
    • (A-2) 5 to 50, preferably 1 5 to 45% of an aromatic polyol and optionally
    • (A-3) 0 to 25, preferably 1 to 10% of modifying compounds with at least two epoxy-reactive groups,
  • (B) a dispersant
    • (B-1) a condensation product
      • (B-11) an aliphatic polyol with a weight average molar mass (M _w ) of 200 to 20,000 g / mol and
      • (B-12) an epoxy compound with at least two epoxy groups per molecule and preferably an epoxy group content of 500 to 10,000 mmol / kg (epoxy equivalent weight of 100 to 2000 g / mol),
  • preferably the ratio of the number of hydroxyl groups to the number of epoxy groups is 1: 0.5 to 1: 3.5 and the epoxy group content of this condensation product is between 2.5 and 200 mmol / kg (epoxy equivalent weight between 5000 and 400,000 g / mol) lies, and
    • (B-2) optionally further, preferably nonionic surfactants,
  • (C) a diluent consisting of
    • (C-1) low molecular weight, liquid epoxy-functional compounds, and
    • (C-2) ethylenically unsaturated, otherwise inert or optionally functional monomers which are optionally capable of radical polymerization or copolymerization
  • (D) and water and optionally organic solvents
• (II) an aqueous curing agent for the modified epoxy resin (I), which is suitable for curing at room temperature or at elevated temperatures (forced drying),
  and if necessary
• (III) customary additives and catalysts,

the components (I) and (II) being used in such proportions by mass that the ratio of the number of epoxy capable of reaction groups in (I) for the number of amine hydrogen atoms in (II) between 1: 0.75 and 1: 2.0.

The invention further relates to a method for producing an aqueous Epoxy resin dispersion (I), characterized in that the epoxy id resin (A) by condensation of components (A-1), (A-2) and given if (A-3) at elevated temperatures in the presence of condensation catalyst is produced, then the dilution at a lower temperature ning agent (C-1) is added, then the dispersant (B) is homogeneous is siert and an aqueous dispersion by portionwise addition of Water (D) is obtained.

The invention further relates to a method for producing an aqueous Epoxy-polyacrylate dispersion (I), characterized in that first Epoxy resin (A) by condensation of components (A-1), (A-2) and against also (A-3) at elevated temperatures in the presence of condensation catalysts is produced, then at a lower temperature at least a portion of the diluent (C) is added and added if necessary, a partial reaction of the monomers (C-2) with the epoxy resin (A) is carried out, the dispersant (B) is homogenized and a  obtain aqueous dispersion by metering in water (D) in portions is what you give with the help of a suitable initiator system if necessary, with the addition of the remaining diluent (C) if suitable Temperatures the monomers (C-2) completely in a polymer dispersion transferred. The partial amounts of the diluent that may be used can different composition in terms of quantity and type of ingredients (C-1) and (C-2).

The binder according to the invention is produced by mixing it Dispersion with a suitable hardening agent (II), optionally followed by the Additives known to those skilled in the art according to (III).

The 1,2-epoxy compounds correspond to (A-1) and (B-12) are polyepoxides with an average of at least two epoxy groups per mole cool. These epoxy compounds can be both saturated and unsaturated and aliphatic, cycloaliphatic, aromatic and / or hetero be cyclic and also have hydroxyl groups and polyether units. You can also use such substituents and / or functional groups contain no interference under the mixing or reaction conditions cause side reactions, for example alkyl or arylsub substituents, ether groups and the like.

These are preferably polyglycidyl ethers based on more valuable, preferably dihydric alcohols, phenols, hydrogenation products of these phenols and / or of novolaks (reaction products of mono- or polyhydric phenols with aldehydes, especially formaldehyde in the presence of acidic catalysts). The epoxy group contents of this epoxy connections are preferably between 500 and 11,000, in particular between 2800 and 10,000 mmol / kg (epoxy equivalent weights between 90 and 2000, especially between 100 and 350 g / mol).  

Examples of polyhydric phenols are: resorcinol, hydro quinone, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), dihydroxydiphenyl methane (bisphenol F, possibly mixtures of isomers), tetrabromobisphenol A, 4,4'-di hydroxydiphenylcyclohexane, 4,4'-dihydroxy-3,3'-dimethyldiphenylpropane, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxybenzophenone, bis- (4-hydroxy-phe nyl) -1,1-ethane, 2,2-bis [4- (2-hydroxypropoxy) phenyl] propane, bis- (4-hydroxy phenyl) -1,1-isobutane, 2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, bis- (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, tris (4-hydroxyphe nyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone u. a. and the halogenation and hydrogenation products mentioned above connections. Bisphenol A is particularly preferred here.

Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, Triethylene glycol, polyethylene glycols (n = 1 to 35), 1,2-propylene glycol, Polypropylene glycols (n = 1 to 15), 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2,6-hexanetriol, glycerin, neopentanglycol, 1,4-dimethylolcyclohexane, trimethylolethane, trimethylolpropane, but also Block copolymers of ethylene oxide, propylene oxide, etc., and also ethoxylated and propoxylated bisphenols such as B. propoxylated bisphenol A. Poly Ethylene glycols and polypropylene glycols (n = 8-10) are special prefers.

Polyglycidyl esters of polycarboxylic acids can also be used, which is obtained by the reaction of epichlorohydrin or similar epoxy compound with an aliphatic, cycloaliphatic or aromatic polycar bonic acid, such as oxalic acid, succinic acid, adipic acid, glutaric acid, phthal acid, terephthalic acid, hexahydrophthalic acid, 2,6-naphthalenedicarboxylic acid and dimerized linolenic acid, or with acidic polyesters. At Games are diglycidyl adipate, diglycidyl phthalate and He xahydrophthalic acid diglycidyl ester.  

A detailed list of suitable epoxy compounds can be found in the manual "Epoxy Compounds and Epoxy Resins" by A.M. Paquin, Springer Verlag, Berlin 1958, Chapter IV and in Lee, Neville, "Handbook of Epoxy Resins ", McGraw-Hill Book Co., 1967, Chapter 2. The epoxies mentioned d compounds can be used individually or in a mixture.

The aromatic polyols corresponding to (A-2) are preferably the aro matical OH group-containing compounds in question, the above in the Components (A-1) and (B-12) have been described, i.e. polyvalent, preferably dihydric phenols, their halogenation products and / or Novolaks. Bisphenol A is also particularly preferred here.

The modifying compounds according to (A-3) are Ver bonds with at least two functional groups, which are used for the reaction with the epoxy groups of component (A-1), and which ones do not classify as aromatic polyols according to (A-2). your Use can be made to own desirable modification through targeted modification properties of the base resin (A). These can be polyamines (e.g. ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene penta min, etc.), polyoxyalkylene oxides with terminal amino groups (e.g. the Jeffamine® from TEXACO and Novamin® types), aliphatic and aro Matic polycarboxylic acids with 2 to 60 carbon atoms (e.g. maleic acid re, fumaric acid, phthalic acid, succinic acid, dimeric and trimeric fatty acids etc. and their anhydrides, if available) and aliphatic polyols (e.g. Ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane and ethanol, neopentylglycol, glycerin etc.) han deln. Dimeric fatty acids with a content of 20 are particularly preferred up to 50 carbon atoms and Jeffamine®.  

The polyols of component (B-1) are preferably polyether polyols (polyoxyalkylene glycols) with weight-average molar masses (M _w ; gel permeation chromatography; polystyrene standard) of preferably between 600 and 12,000, in particular 2000 to 8000 g / mol and OH- Numbers expediently from 10 to 600, preferably 15 to 120 mg / g. These polyether polyols preferably have only terminal, primary OH groups. For example, block copolymers of ethylene oxide and propylene oxide as well as polyethylene, polypropylene, polybutylene glycols may be mentioned here, it also being possible to use mixtures of the respective polyalkylene glycols. Polyethylene glycols are preferably used.

In addition, dispersants (B-1) according to the invention can also be wide re dispersant (B-2) anionic, cationic and preferably nonionic be used. Alkylbenzenesulfonates, primary, are suitable and secondary alkane sulfonates, α-olefin sulfonates, alkyl sulfates and alkyl ethers sulfates as anionic and quaternary ammonium compounds as cationi cal surfactants in question, the ionic groups not with the epoxy groups may interact. However, the use of non-ionic is preferred shear surfactants such as ethoxylated or ether / propoxylated alcohols, oxo alcohols, Alkylphenols (e.g. Arcopal® from Hoechst), castor oils, esters, glycerin stearates, fatty acids, fatty amines, fatty alcohols, but also z. B. ethylene oxide Propylene oxide block copolymers (e.g. Pluronic® from BASF). Also the Emulsifiers specifically described for dispersing epoxy resins can NEN are used such. B. from US 4,423,201 and US 4,446,256 (Products from polyalkylene glycols, diisocyanates and bisphenols), EP 0 497 404 (Products from alkoxypolyalkylene glycols, anhydrides and alkylene oxides, Epoxy alcohols or diglycidyl ethers), WO 91/10695 (products made from polygly cidyl ethers, bifunctional compounds and alkoxypolyalkylene glycols), EP 0 109 173 (products made from polyoxyalkylene polyamines and epoxy resins) and  DE 41 36 943 (Products from polyalkylene glycols with diisocyanates and Polyepoxides).

As component (C-1), low molecular weight liquid epoxy functional compound low molecular weight ether of glycidyl alcohol with a and polyhydric phenols, alkyl-substituted phenols and mono- and polyhydric aliphatic branched and unbranched alcohols and Esters of branched or unbranched aliphatic carboxylic acids with 2 to 40 carbon atoms, which u. a. under the term reactive thinners are known, e.g. B. para-tert-butylphenylglycidyl ether, n-butylglycidyl ether, Phenylglycidyl ether, ortho-cresyl glycidyl ether, butanediol diglycidyl ether, Hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, dimethylolcycloh exandiglycidyl ether, 2-ethylhexyl glycidyl ether, higher alkyl glycidyl ether etc. (e.g. the reactive thinners of the Grilonit® RV series from Ems, Epodil® from Anchor or Eurepox®, RV from Schering), Versatic acid glycidyls ster (Cardura® E 10 from Shell), liquid polyoxyalkylene glycol diglycidy ether (e.g. Beckopox® EP 075 from Hoechst), but also liquid ep oxide resins such as B. bisphenol A and F diglycidyl ether. Component (C-1) is called reactive diluents below for the sake of simplicity. Preferred reactive diluents are hexanediol diglycidyl ether and para-tert.- Butylphenylglycidyl ether.

As monomers according to (C-2) come all ethylenically unsaturated ver bonds in question, which for free-radical polymerization in aqueous Are capable and not undesirable at room temperature with the emulsion existing epoxy resin dispersion interact. These include acrylic, metha cryl and higher alkacrylic acids, and their alkyl esters (C₁ to C₁₈ alkyl (meth) acrylates, e.g. B. methyl acrylate and methacrylate, ethyl acrylate and meth acrylate, n- and iso-propyl acrylate and methacrylate, n-, so- and tert-butyl acrylate, n- and tert-butyl methacrylate, 2-ethylhexyl acrylate and methacrylate,  4-tert-butylcyclohexyl acrylate, isobornyl acrylate and methacrylate etc.) and Derivatives (e.g. acrylonitrile), but also vinyl derivatives (e.g. styrene, α-methylstyrene, Vinyl toluenes, vinyl acetate, vinyl chloride, vinylidene chloride, N-vinyl pyrrolidone etc.) and α, β-unsaturated carboxylic acids such as maleic acid, fumaric acid, Itaconic acid etc. and their derivatives, but also alkenes such as isoprene and Butadiene. The monomers can also contain functional groups who participate in the hardening reaction to be sought later, so are suitable for. B. specifically glycidyl-functional monomers (e.g. glycidyl methacrylate, glycidyl acrylate). Finally, multi-functional Monomers, be it in terms of polymerization or curing be so B. 1,6-hexanediol diacrylate, divinylbenzene etc.

If appropriate, solvents (D) can also be added to the dispersion the, mass fraction up to 10% are preferred. As an organic solvent Solvents are particularly suitable here: glycols, mono- and dietary and esters of glycols with alcohols and acids, aliphatic alcohols with optionally branched alkyl radicals of 1 to 12 carbon atoms, cycloaliphatic and araliphatic alcohols as well as esters and ketones, where these solvents can be used individually or in a mixture. As Examples include: ethylene glycol, ethylene glycol monomethyl ether, Ethylene glycol dimethyl ether, butyl glycol, methoxypropanol, ethoxypropanol, Ethanol, 1- and 2-propanol, butanol, cyclohexanol, benzyl alcohol, vinegar Acid ethyl ester, acetone such as methyl isobutyl ketone, but also aromatics such as Toluene or xylene can be used. Preferred solvents are Butylglycol, methoxypropanol, methoxybutanol, isopropoxypropanol, eth oxypropanol, 2-propanol and / or benzyl alcohol.

After the dispersion process, the epoxy resin dispersion Emulsion polymerization initiated at a temperature which is a rapid, ensures complete reaction and at the same time the dispersion is not ge  endangers. For this purpose, such thermal nature or Re come as initiators dox systems, all of which are well known to those skilled in the art. Thermi initiators are peroxides, hydroperoxides, peresters, diazo compounds, e.g. B. dibenzoyl peroxide, acetyl peroxide, benzoyl hydroperoxide, tert-butylhydro peroxide, di-tert-butyl peroxide, lauroyl peroxide, butyryl peroxide, diisopropylbene zolhydroperoxid, Cumolhydroperoxid, Paramenthanhydroperoxid, Diacetylper oxide, di-α-cumyl peroxide, dipropyl peroxide, diisopropyl peroxide, isopropyl tert.- Butyl peroxide, butyl tert-butyl peroxide, dilauroyl peroxide, difuroyl peroxide, Ditriphenylmethyl peroxide, bis (p-methoxybenzoyl) peroxide, p-monomethoxyben zoyl peroxide, rubene peroxide, ascaridol peroxide, tert-butyl peroxybenzoate, Diethyl peroxy terephthalate, propyl hydroperoxide, isopropyl hydroperoxide, n- Butyl hydroperoxide, tert-butyl hydroperoxide, cyclohexyl hydroperoxide, trans Decalin hydroperoxide, α-methylbenzyl hydroperoxide, α-methyl-α-ethylbenzyl hydroperoxide, tetralin hydroperoxide, triphenylmethyl hydroperoxide, diphenyl methyl hydroperoxide, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 1,1-bis (tert-butyl peroxy) cyclohexane and tert-butyl perbenzoate. Redox system me can be chosen from oxidants such as B. hydrogen peroxide, tert-butyl hydroperoxide, persulfates, in combination with reducing agents such as alpha-hydroxy ketones, ascorbic acid, hydrazine and sulfites, bisulfites, Metasul fite or hydrosulfite. Initiators should preferably be used, which generate little or no ionic compounds to make water sensitive not unnecessarily increase the later burned-in films. A be a particularly preferred system is tert-butyl hydroperoxide / ascorbic acid.

As hardeners (II) for the epoxy resins (I) of the invention, these can be known hardening agents or hardening compounds (epoxy hardeners) are used such as basic hardeners (amine hardeners), for example polyamines, Mann i-bases, adducts of amines with polymers such as polyepoxides and Polyamidoamines.  

The curing of the epoxy resin dispersions (I) according to the invention is furthermore by so-called latent curing agents, d. H. Connections that are only at higher temperature, for example at 60 to 250 ° C, its crosslinking Developing an effect on epoxy compounds is possible. examples for such hardeners are urea, dicyandiamide, imidazole and imidazoline as well (e.g. with alkyl or alkoxy groups) substituted imidazoles and imidazolines, Benzo- and acetoguanamine, guanidine, hydrazide and derivatives of the above Links. But also z. B. are melamine resins or acidic curing agents conceivable. Of these latent curing agents, dicyandiamide is preferred used.

Examples of basic hardening agents, preferably the preferred hardening agent at room temperature and / or lower temperatures (cold amine hardness ter), which is generally in the ratio of the number of epoxy groups to the number of Amine hydrogen atoms from 1 to (0.75 to 2.0) are used Polyalkylene amines such as diethylene triamine, triethylene tetramine, tetraethylene pen tamin, pentaethylene hexamine and. a., also 2,2,4- and / or 2,4,4-trimethylhexa methylenediamine, bis (3-aminopropyl) amine, 1,4-bis (3-aminopropyl) piperazine, N, N-bis (3-aminopropyl) ethylenediamine, neopentanediamine, 2-methyl-1,5- pentanediamine, 1,3-diaminopentane, hexamethylenediamine and the like. a., and cycloali phatic amines such as 1,2- or 1,3-diaminocyclohexane, 1,4-diamino-3,6- diethylcyclohexane, 1,2-diamino-4-ethylcyclohexane, 1-cyclohexyl-3,4-diamino cyclohexane, isophoronediamine and reaction products thereof, 4,4'-diamino dicyclohexyl methane and propane, 2,2-bis (4-aminocyclohexyl) methane and -propane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3-amino-1-cyclohex yl-aminopropane, 1,3- and 1,4-bis (aminomethyl) cyclohexane.

Araliphatic amines used are, in particular, those in which aliphatic amino groups are present, e.g. B. meta- and para-xylylendi amine, and / or their hydrogenation products.  

The amines mentioned can be used alone or as mixtures.

Suitable Mannich bases are obtained by condensation of polyamines preferably diethylenetriamine, triethylenetetramine, isophoronediamine, 2,2,4- or 2,4,4-trimethylhexamethylene diamine, 1,3- and 1,4-bis (aminomethyl) cyclohe xan, especially meta- and para-xylylenediamine with aldehydes, preferred as formaldehyde and mono- or polyhydric phenols with at least a core position reactive towards aldehydes, for example the ver various cresols and xylenols, para-tert-butylphenol, resorcinol, 4,4'- Dihydroxydiphenylmethane, 4,4'-dihydroxy-diphenyl-2,2-propane, preferably but made phenol.

Examples of reaction products include amine-epoxy adducts Polyamines such as B. ethylene diamine, propylene diamine, hexamethylene diamine, 2,2,4-, 2,4,4-trimethylhexamethylene diamine, meta-xylylenediamine and / or Bis (aminomethyl) cyclohexane with terminal mono- or polyepoxides, such as B. propylene oxide, hexene oxide, cyclohexene oxide, or with glycidyl ethers such as phenyl glycidyl ether, tert-butyl glycidyl ether, ethyl hexyl glycidyl ether, Butyl glycidyl ether or with glycidyl esters, such as that from Shell sold glycidyl ester of versatic acid, Cardura® E 10, or the under (A-1) mentioned polyglycidyl ethers and esters.

Polyamidoamines used to cure the epoxy resin dispersion according to the invention NEN can be used, for example, by implementing Polyamines with mono- or polycarboxylic acids, e.g. B. dimerized fatty acids, receive.

Preferred amine hardeners in addition to the above-mentioned polyamines water-soluble polyoxyalkylene diamines and polyamines with molar masses of 100 to 2000 g / mol, e.g. B. from Texaco under the trademark  Products distributed by Jeffamine®, as well as the easily dispersible in water Hardening agents, as described in DE-A 23 32 177 and EP-A 0 000 605 are described, e.g. B. modified amine adducts.

To achieve faster and / or more complete curing those from the epoxy resin dispersions according to the invention with the named Coatings available from amine hardeners also range from 15 to 120 minutes to 50 to 120 ° C are heated (so-called forced drying).

As usual additives within the meaning of (III), which may be in the fiction Moderate dispersions or binders may be present here for example the usual paint additives such as pigments, pigment pastes, Antioxidants, leveling agents or thickeners, defoamers / deaerators and / or wetting agents, reactive thinners, fillers, catalysts, preserves means, protective colloids and the like. These additives, like also the hardeners, if necessary, can only immediately prior to the dispersion be added to the processing.

To prepare the dispersions according to the invention, the Ep oxide resin (A) by condensation of components (A-1) and (A-2) also with (A-3), at elevated temperatures, generally at 100 to 220 ° C, preferably at 150 to 180 ° C, in the presence of a Kon densation accelerating catalyst.

Suitable condensation catalysts are, for example, phosphines, such as Triphenylphosphine, phosphonium salts such as e.g. B. Benzyltrimethylphosphonium chloride, tertiary amines such as N, N-dimethylbenzylamine, quaternary ammonium salts such as B. tetramethylammonium chloride, alkali metal hydroxides such as sodium hy hydroxide and lithium hydroxide, alkali carbonates such as sodium carbonate and Li thium carbonate, alkali salts of organic acids, such as. B. sodium formate,  Lithium benzoate and lithium stearate and Lewis acids, such as. B. boron trifluoride and its complexes, titanium tetrachloride, tin chloride and triethyloxonium tetra fluoroborate.

If two or more epoxy compounds (A-1) are used, the Condensation reaction is preferably carried out in two stages, wherein in a first reaction one or more components (A-1) with the compo nenten according to (A-2) and optionally (A-3) in such amounts ratio are implemented that this first condensation product Epoxy group content below 200 mmol / kg, preferably below 50 mmol / kg has (epoxy equivalent weight greater than 5000 g / mol, preferably greater than 20,000 g / mol) and still has free phenolic groups, and in a further condensation reaction this first condensation product is reacted with further epoxy compounds according to (A-1), so that finally the desired epoxy resin (A) is obtained.

The dispersant (B-1) is by condensation of the polyether mentioned polyols with the polyglycidyl ethers according to (A-1) in the presence of suitable Catalysts at 50 to 200 ° C, preferably at 90 to 170 ° C, Herge represents, the ratio of the number of hydroxyl groups to the number of Epoxy groups 1: 0.5 to 1: 8, preferably 1: 0.85 to 1: 4 and the epoxy Group content of the condensation product 2.5 to 8500 mmol / kg (Epoxidä equivalent weight is 120 g / mol to 400,000 g / mol).

Suitable catalysts for the preparation of the dispersant (B-1) strong inorganic and organic bases, such as alkali and alkaline earth Potash hydroxides and oxides (e.g. lithium hydroxide, sodium hydroxide, potassium hy hydroxide, calcium hydroxide, barium hydroxide, magnesium oxide, calcium oxide etc.), alkali alcoholates (e.g. sodium methylate, lithium methylate, sodium ethyl Iate, potassium dodecylate etc.) and the alkali salts of carboxylic acids (e.g. Sodium and lithium stearate or lactate) and hydrides (e.g. alkali and alkaline earth  potash hydrides and borohydrides such as sodium hydride, calcium hydride and sodium borohydride, etc.). Strong inorganic and organic are also suitable Protonic acids (e.g. phosphoric acid, sulfuric acid, tetrafluoroboric acid and Benzenesulfonic acid etc.) as well as Lewis acids (e.g. tin (IV) chloride, Ti tan (IV) chloride, titanium (IV) isopropylate, triethyloxonium tetrafluoroborate and Boron trifluoride and its complexes, for example with phosphoric acid, acetic acid (1: 1 and 1: 2), methanol, diethyl ether, tetrahydrofuran, phenol, ethylene glycol monoethyl ether, polyethylene glycol (MG 200), dimethyl sulfoxide, di n-butyl ether, di-n-hexyl ether, succinic acid and aliphatic, cycloaliphati cal, araliphatic amines and nitrogen heterocycles, etc.). But also certain inorganic salts are well suited as catalysts, such as. B. alkali and alkaline earth fluorides, phosphates and stannates.

The complexes of BF₃ with diethyl ether are preferred as catalysts and acetic acid and aqueous tetrafluoroboric acid. The masses proportion of catalyst is generally 0.1 to 5, preferably 0.1 to 1% in the reaction mixture. For better dosing, the catalyst can be in a solvent such as diethyl ether, a glycol or cyclic ether, Ketones and the like can be diluted.

To prepare the dispersant, the gemi to be reacted are heated up from compounds containing hydroxyl groups and epoxy groups to the temperature at which the condensation with sufficient speed speed d. H. in 30 min to 5 hours. You follow the implementation expedient about the decrease in the epoxy group content. The reaction can can be stopped by cooling below the reaction temperature.

The condensation product thus obtained can be used as such (100%) as Dis pergiermittel (B-1) for the production of the dispersions according to the invention be applied. However, it is preferred for reasons of better hand  availability a mixture with a mass fraction of 20 to 99, preferably as 40 to 60% of the condensation product, preferably with water or optionally with a preferably aqueous medium consisting of Mass fractions of up to 100, preferably up to 75%, of an organic Solvent produced and this mixture as a dispersant (B-1) used. Particularly suitable organic solvents are glycols, Mo no- and dieters and esters of glycols with alcohols and acids, aliphati cal alcohols with optionally branched alkyl radicals from 1 to 12 Koh lenstoffatomen, cycloaliphatic and araliphatic alcohols and esters and Ketones into consideration, these solvents being used individually or in a mixture can be set. Examples include: ethylene glycol, ethylene glycol colmonomethyl ether, ethylene glycol dimethyl ether, butyl glycol, methoxypro panol, ethoxypropanol, ethanol, 1- and 2-propanol, butanol, cyclohexanol, Benzyl alcohol, ethyl acetate, acetone such as methyl isobutyl ketone. Be butyl glycol, methoxypropanol, ethoxypropanol, 2-propanol, Hydroxyethyl or propyl methacrylate and / or benzyl alcohol used, or the monomers listed under (C-1).

The diluent (C) as a total amount at once before the Dis pergieren added, it serves as a viscosity reducer and facilitates the Dispersion, or it can take place during a larger amount in part Dispersing process be present, and the rest will be after dispersing tion, e.g. B. continuously added during the emulsion polymerization. The two subsets must be of the type and composition components (C-1) and possibly (C-2) are not identical. In this way With epoxy-polyacrylate dispersions, core-shell particles can be targeted testify. The presence of the diluent during the dispersion has the sense that the viscosity maximum in the phase inversion W / O → O / W not due to inert solvents remaining in the finished dispersion must be lowered, as described in DE 41 28 487. Consequently  the formulation of completely solvent-free dispersions succeeds - another one considerable improvement over the prior art. Too high Content during the dispersing process, however, the viscosity would be too high lower, the shear force to be entered for the division processes could not be built up more. Therefore, if necessary, the distribution of the total quantity in two appropriate subsets necessary.

Reactive diluents (C-1) are used to improve the application technology to control the properties of the dispersion, e.g. B. Lowering the minimum film formation temperature, extension of processing time, improvement of gloss, shear stability and stability against freeze-thaw cycles, targeted Influencing hardness and elasticity etc. The advantage over the Use of organic solvents is that these reactive thinner in the film during the curing reaction and thus not lead to the undesired emission of organic components, the An So the freedom from solvents is preserved. The addition of the reak tivverdünners before the dispersion process has the main advantage that this is emulsified significantly better with less effort than in the case of one subsequent addition to the finished dispersion, resulting in an improved Quality of the coating leads. In this case there are reactive thinners and Base resin in common micelles before, what by subsequent Einhomoge The reactive diluent cannot be achieved. The reactive reactant content thinner is to be added to the solid of the binder or the lacquer.

The epoxy resin (A) is used to produce the epoxy-polyacrylate dispersion at temperatures from 60 to 200 ° C, preferably from 70 to 120 ° C, the Monomers (C-2) - possibly stabilized with suitable ones known to the person skilled in the art Inhibitor and reactive diluents (C-1) or a suitable portion, then the dispersants (B-1) and optionally (B-2), optionally followed by organic Solvent (D) added and 15 to 180, preferably 30 to 90 minutes  ten, stirred. Optionally, one can be added after the addition of the monomers Carry out reaction between epoxy resin and the monomers, such as. B. Addition of carboxyl or amine monomers to the epoxy groups or Grafting on aliphatic carbon atoms of the epoxy components (A) and (C-2) before adding the dispersant.

Then at temperatures of 30 to 100 ° C, preferably 50 to 90 ° C, the corresponding amount of water (D), preferably in several parts gene, metered in with vigorous stirring, which causes the aqueous dispersion arises. Suitable defoamers / deaerators Additives are added. The dispersion is advantageously carried out with the aid of suitable dispersing apparatus, for example one high-speed paddle stirrer, a multi-impulse spiral stirrer, a Kol loid mill, a homogenizer, a dissolver or another High-speed mixer with high shear force. This process becomes very detailed described in DE-A 41 28 487.

In the thus obtained, monomer-containing and reactive diluent-containing Ep oxide resin dispersion now becomes the emulsion polymer at a suitable temperature initiated. The temperature must be high enough for a rapid polymerization rate is achieved, on the other hand, due to a too high Temperature the stability of the dispersion cannot be jeopardized. With redox For initiators, the oxidizing agent is preferred along with the diluent homogenized water, and the reducing agent continuously added - but all conceivable variants are also according to the invention. At a higher amount of monomers than is required for the dispersion also the remaining amount of the monomers (C-2) metered in, here specifically the Representation of core-shell acrylic particles is possible to improve the properties to control the dispersion in the desired manner. The preferred temperature The range for emulsion polymerization is 60 to 90 ° C, the reaction  Control is carried out via solid-state determination or gas chromatography. A Undesired viscosity increase can be caused by adding water be compared.

The mass ratio of epoxy resin (A) to addition polymers (C-2) is from 99.5: 0.5 to 20:80, preferably between 5:95 and 50:50. The polymer (C-1) may contain glycidyl groups Monomers, preferably mass fractions of 2.5 to 25%. The mass fraction of Reactive thinner (C-1) can be up to 25% based on the mass of the polymer right (A) and (C-2). The mass fraction of dispersant (B) relates refer to all non-water-soluble components of the dispersion, d. H. on the epoxy resin (A), the polymer (C-2) and reactive diluent (C-1) and lies between 1 and 25%, preferably between 2 and 15%. The together setting of the dispersant for (B-1) :( B-2) is between 0: 100 and 100: 0, preferably over 75:25. The solid mass fraction of the invention according dispersion is between 30 and 90%, but preferably from 55 to 75%, the dispersion having a mass fraction of up to 10% solvent can contain, but is preferably solvent-free.

The epoxy resin corresponding to (A) has the dispersions according to the invention preferably an epoxy group content of 250 to 3000 mmol / kg, ins particularly 300 to 2500 mmol / kg (epoxy equivalent weight of 350 to 4000, especially from 400 to 3000). The average particle size of the dispersed resin is usually not higher than 1.0 µm and is preferably 0.2 to 0.8 µm. The particle size of the polyacrylate (C-2) is less than 0.5 µm, preferably less than 0.25 µm. Also lie in the case of grafting the particle sizes of the dispersions according to the invention are less than 1 μm.

The viscosity of these dispersions is generally between 200 and 30,000 mPas, preferably between 750 and 7,000 mPas.  

The dispersions of the invention are notable for their good properties Storage stability from that on the low middle part for secondary dispersions size can be attributed, especially due to its very small size or lack of organic solvent content and especially due to the much higher solid. Compared to already known epoxy Resin dispersions or epoxy-acrylate dispersions have those with the Coatings obtainable according to the invention also have a coating A number of technical advantages, e.g. B. low water sensitivity, good elasticity with very high hardness, good to very good adhesion to the various substrates, excellent corrosion protection Coating of metallic materials, extension of the pot life u. a.

The hardeners and other hardenable resins according to (II) are preferably first added immediately before application of the dispersion.

Because of their excellent technical characteristics already mentioned properties, for example with regard to adhesion, very high hardness, corrosion protective effect, water and chemical resistance u. a., are the dispersions according to the invention in combination with suitable curing agents and additives for the production of coatings, intermediate coating coatings, coating materials, molding compounds and curable compounds for the different areas of application. For example, they can be used for Production of protective and / or decorative coatings on the difference Lichsten, especially rough and porous substrates such. B. wood, minera substrates (e.g. concrete and stone), glass, plastics (e.g. poly ethylene, polypropylene, etc.), composite materials, ceramics and pre-treated th or not pretreated metals.

The dispersions of the invention are also excellent for the one suitable for paint coating. As such, the adhesive coating layer can  remain unchanged, but it can also be used as an intermediate layer, i.e. as a sub layer layer for further coatings, which in turn serve from the same or another conventional coating material can exist.

Epoxy-polyacrylate dispersions can be used with a suitable choice of the reactive thinner (C-1) and the monomers (C-2) matt clear coats who those whose other property profile is still good (good adhesion to various substrates, very high hardness, good resistance etc.).

Suitable for their good dilutability and their favorable properties the dispersions of the invention are also for additional use in electrocoating.

Another possibility is the use of the disper according to the invention sions for the production of water-dilutable adhesives. Also as a binder these are used for textile, organic and / or inorganic materials bar. They can also serve as an additive to plastic cements.

When used as a coating agent or as a predominantly aqueous Varnish is applied to the substrate using conventional methods, such as brushing, spraying, dipping or rolling. The Be Coatings are provided, provided that no hardening agents are used for cold hardening be applied by heating to 80 to 250 ° C for one to cure sufficient time, generally 5 to 60 minutes, cured.

Possibly. required additives according to (III) and - if for the intended A sentence desired - additional hardening agents are added in such quantities sets as required for the corresponding purpose and the specialist  are known. In this case, the user is free to choose which one Solids and solvent content he chooses.

The following examples describe the preparation of the epoxy resin (A), the Dispersant (B-1), the dispersion (A) + (B) + (C) or the binder (A) + (B) + (C) + (II) and its application, referring to the restrict particularly preferred, absolutely solvent-free systems.

EXAMPLES I. Epoxy resins (A)

• I.1 A commercial epoxy resin based on bisphenol A and Epichlorohydrin with an epoxy group content of approx. 2100 to 2300 mmol / kg (epoxy equivalent weight from 450 to 470 g / mol) (e.g. Beckopox® EP 301 or Epikote® 1001).
• I.2 A flexible epoxy resin made by reacting 150 g Diglycidyl ether of polypropylene glycol with an epoxy group content of 2750 to 3150 mmol / kg (EV value from 320 to 360 g / mol) and 234 g bisphe nol A at 160 ° C with approx. 0.2 g triphenylphosphine until complete Disappearance of the epoxy groups, and further implementation of this phenoli Intermediate product with 750 g bisphenol A diglycidyl ether (epoxy group content 5400 mmol / kg; EV = 185 g / mol) under the same conditions up to an epoxy group content of 2100 to 2300 mmol / kg (EV value from approx. 460 to 470 g / mol).
• I.3 A self-dispersing epoxy resin of the Beckopox® EP 301 type, obtained by reacting bisphenol A, its diglycidyl ether (epoxy group content 5405 mmol / kg; EV value 1 85 g / mol) and a solvent  free dispersant (β-1) at temperatures around 160 ° C, analogous to DE- A 36 43 751 described.

II. Dispersant (B-1)

309 g of technical polyethylene glycol with a weight-average molar mass (M _w ) of 4000 g / mol and 34.1 g of a polyglycidyl ether based on bisphenol A with an epoxide group content of 5460 mmol / kg (epoxide equivalent weight of 183 g / mol) were combined Heated 100 ° C and mixed with stirring with 0.35 ml of 50% aqueous tetrafluoroboric acid. The ratio of the number of hydroxyl groups to the number of epoxy groups was 1: 1.20. The mixture was further heated to 130 ° C and held at this temperature until the epoxy group content of the condensation product was about 2.9 mmol / kg (epoxy equivalent weight about 350,000 g / mol). After cooling, the emulsifier had a brittle, waxy solid consistency and can be used directly for the production of the epoxy resin I.3.

250 g of this condensation product were stirred and gently Warm up to approx. 80 ° C dissolved in 250 g water. The light yellow, clear emulsifier solution had a viscosity (measured according to Brookfield, 25 ° C) of 3500 mPa · s and a solid mass fraction of 50%.  

III. Dispersions (A) + (B) + (C)

Abbreviations for reactive thinners, monomers and solvents

General working instructions for epoxy resin dispersions

423 g of epoxy resin (A) are melted and at 100 ° C with reactive thinner homogenized according to (C-1) and at 90 ° C with 81 g dispersant if necessary medium (B) mixed (resins 1.1 and 1.2). 50 to 90 g are rapidly stirred at 80.degree Add water, stir until phase inversion and gradually give approx. 170 g Water, the temperature at the end being 60 ° C. It will be with some water adjusted to about 2500 mPa · s.

General working instructions for epoxy-polyacrylate dispersions

423 g of epoxy resin (A) are melted and diluted at 100 ° C agent according to (C), consisting of reactive diluents (C-1) and monomers (C- 2) homogenized and mixed with 81 g of dispersant (B) at 90 ° C. Man quickly stir in 50 to 90 g of water at 80 ° C, stir until phase inversion and gradually add about 170 g of water, the temperature at the end is at 60 ° C. A mass fraction of 1% is given (based on the Mass of the monomer (C-2)) of tert-butyl hydroperoxide and homogeneous nized 30 minutes, keeping at 60 ° C. You stop at this tempe  rature, adds 0.05 ml of FeSO₄-7 hydrate solution (2% in water) and doses a mass fraction of 1.5% (based on the mass of the monomers) ascorbic acid as a solution in about 45 g of water (syn chron the remaining monomers), with a slight exotherm observed is. After the mixture was allowed to react for a further 1.5 hours at 60 ° C. adjusted to about 2500 mPa · s with a little water.  

table

Abbreviations:
nfA non-volatile components, solids (1 g, 1 h, 125 ° C)
EGG epoxy group content
EV epoxy equivalent weight
TG particle size, photon correlation spectroscopy, monomodal.

IV. Preparation of the coating compositions according to the invention

50 g of dispersion are mixed with a hardening agent according to EP-A 0 000 605 (Example 5c), which was diluted to 40% with water (content of active hydrogen atoms 31 25 mmol / kg; "H-active equivalent weight" 320 g / mol), mixed in a stoichiometric ratio of 1: 1 and as a clear coat mounted on degreased glass plates (wet film thickness approx. 200 µm). Drying takes place at room temperature.

V. Application properties

Explanation of the examination conditions:

• 1. Dust dry: Glass beads scattered on the film can be removed after the no longer remove hardening with a brush.
• 2. Non-tacky: The glass beads can be brushed off after curing remove.
• 3. Pot life ("Pot-life"): After mixing the hardener and dispersion half-hour films with a wet film thickness of 200 microns. The up If the film becomes cloudy after curing, the end of processing is shown time and is entered as the test result.
• 4.Hardness: Pendulum hardness according to König, DIN 53 157.
• 5. Water resistance after 24 h, storage at room temperature: on glass Plates with a film thickness of 200 µm wet film are removed after 24 hours Storage in water tested at room temperature. The rating scale is sufficient from 0 = very good to 5 = bad.  
• 6. MFT curve: The change was made on a Coesfeld (MFT- "D") measuring bench the MFT (minimum film-forming temperature) measured in the course of the reaction time sen. Film formation error (drying temperature lower than MFT) occur in the form of film tears, cloudiness and tarnishing; the tempe Matur is the one in which an intact film is just appearing. On in this way, MFT response time functions for a reaction temp obtained at 20 ° C.

You can clearly see the considerably longer processing time of the system me with reactive thinner. Their films have comparable properties Standard systems on (V.1 and V.3), while the comparison V.2 even against falls back over the standard systems without Texanol over moderate pot life extension occurs. Overall, the invention Coatings only marginally softer than standards V.1 and V.3.

The combination of butyl diglycol + Texanol (V.2) lowers the MFT the most off, but due to the sharp increase in MFT during curing (Crosslinking and evaporation in parallel) still not the expected pot time extension.

V.3 has an insufficiently short pot life, since only methoxypropanol is used here Coalescent is present, which is not effective enough.  

Epoxy acrylate dispersions

While the comparison systems impractically short processing times and V.4 also provides a water-sensitive coating the advantageous effect of the reactive thinners. Only that high film hardness of the standards cannot be achieved.  

Time and type of addition of the reactive diluent

Dispersion III.5 was compared with Beckopox EP 384w if the latter Dispersion of hexanediol diglycidyl ether was added subsequently.

III.5-1: HDDGE dispersed for 5 minutes on a dissolver with a Teflon disk.

III.5-2: HDDGE stirred with spatula for 5 minutes.

This shows that apart from a significant increase in pot life when added of the reactive diluent before dispersing the base resin is not essential There are differences between the dispersions.

Claims (24)

1. Containing aqueous, low-solvent coating compositions

• (I) a base resin dispersion consisting of
  • (A) an epoxy resin, which is a condensation product consisting of parts by mass
    • (A-1) 50 to 95% of one or more epoxy compound (s) with at least two epoxy groups per molecule
    • (A-2) 5 to 50% of an aromatic polyol
  • (B) a dispersant
    • (B-1) a condensation product
      • (B-11) an aliphatic polyol with a weight-average molar mass (M _w ) of 200 to 20,000 g / mol and
      • (B-12) an epoxy compound having at least two epoxy groups per molecule, and
  • (C) a diluent consisting of
    • (C-1) low molecular weight, liquid epoxy-functional compounds, and
  • (D) water,
• (II) an aqueous curing agent for the modified epoxy resin (I), which is suitable for curing at room temperature or at elevated temperatures (forced drying),

the components (I) and (II) being used in such proportions by mass that the ratio of the number of epoxy groups capable of reaction pen in (I) the number of amine hydrogen atoms in (II) between 1: 0.75 and 1: 2.0 lies.   2. Aqueous, low-solvent coating composition according to claim 1, characterized in that the epoxy resin (A) is a condensation product from mass fractions of
(A-1) 55 to 85% of one or more epoxy compound (s) with at least two epoxy groups per molecule and an epoxy group content of 300 to 12,000 mmol / kg
(A-2) 15 to 45% of an aromatic polyol. 3. Aqueous, low-solvent coating composition according to claim 1, characterized in that for the production of the epoxy resin (A) as an additional starting material mass fractions of
(A-3) 1 to 25% of modifying compounds with at least two epoxy-reactive groups can be used. 4. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that in the starting materials for the preparation of the dispersant (B-1) the ratio of the number of OH groups in (B-11) to that of the epoxy groups in (B-12) is 1: 0.5 to 1: 3.5 and the epoxy group content of this condensate tion product (B1) is between 2.5 and 200 mmol / kg. 5. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the dispersant (B) additionally nonionic surfactants contains. 6. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the diluent (C) additionally radical polymeri contains olefinically unsaturated compounds (C-2) which are otherwise inert are.   7. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that a mass fraction of up to 10% Lö in the dispersion is included. 8. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the epoxy compounds according to (A-1) and (B-12) are independent are gigantic selected from polyglycidyl ethers of polyvalent Alcohols, phenols, hydrogenated phenols and novolaks as well as polyglycidyl esters of aliphatic, cycloaliphatic and aromatic polycarboxylic acids with 2 to 40 carbon atoms with an epoxy group content between 300 and 12,000 mmol / kg. 9. Aqueous, low-solvent coating composition according to claim S, characterized characterized in that the epoxy group content of (A-1) and (B-12), respectively is independently between 500 and 11,000 mmol / kg. 10. Aqueous, low-solvent coating composition according to claim 8, characterized characterized in that the epoxy group content of (A-1) and (B-12), respectively independently between 2800 and 10,000 mmol / kg. 11. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the aromatic polyols (A-2) are selected from two and polyvalent mono- and polynuclear phenols, their halogenation products, as well as the novolaks. 12. Aqueous, low-solvent coating composition according to claim 3, characterized characterized in that as modifying compounds (A-3) of aromatic Polyols different bodies with at least two opposite epoxy groups reactive functional groups are used.   13. Aqueous, low-solvent coating composition according to claim 3, characterized characterized in that the modifying compounds (A-3) are selected from aliphatic polyamines, polyoxyalkylene mono- and diamines, aliphatic and aromatic polycarboxylic acids having 2 to 60 carbon atoms, and aliphatic polyols. 14. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the compounds (B-1) are selected from polyoxyal kylene polyglycols with weight-average molar masses from 600 to 12,000 g / mol. 15. Aqueous, low-solvent coating composition according to claim 1, characterized characterized in that the compounds (C-1) are selected from the lower molecular ethers of glycidyl alcohol with mono- and polyhydric phenols, alkyl-substituted phenols and mono- and polyvalent aliphatic branches th and unbranched alcohols and esters of branched or unbranched ten aliphatic carboxylic acids having 2 to 40 carbon atoms. 16. Aqueous, low-solvent coating composition according to claim 6, characterized characterized in that the compounds (C-2) are selected from the esters of α, β-olefinically unsaturated carboxylic acids with aliphatic alcohols with 1 up to 18 carbon atoms, vinyl aromatics, vinyl esters and vinyl halides, α, β- olefinically unsaturated carboxylic acids and their amides and nitriles. 17. Aqueous, low-solvent coating composition according to claim, characterized characterized in that the curing agents (II) are selected from polyamines, Mannich bases, epoxy-amine adducts with free amino groups, polyamidoa mines and latent hardening agents.   18. Aqueous, low-solvent coating composition according to claim 17, characterized characterized in that the latent curing agents are selected from urea, Dicyandiamide, (substituted) imidazole, (substituted) imidazoline, guanidine, Aceto and benzo guanamine. 19. Process for the preparation of the aqueous modified epoxy resin dispersion (I), characterized in that first the epoxy resin (A) by condensate tion of components (A-1), (A-2) and optionally (A-3) at elevated temperatures temperatures is produced in the presence of condensation catalysts closing at least a portion of the dilution at a lower temperature is added by means of (C) and optionally a partial reaction of the mono mer (C-2) with the epoxy resin (A), then the dispersant (B) is homogenized and an aqueous dispersion is added in portions dosing of water (D) is obtained, followed by an appropriate Initiator system and optionally with the addition of the remaining dilution by means of (C) at suitable temperatures, the monomers (C-2) completely into one Polymer dispersion transferred. 20. Aqueous, low-solvent coating compositions produced according to Ver drive from claim 19. 21. Coatings produced with the coating composition according to claim 1. 22. Matt clear lacquers containing aqueous dispersions according to claim 1. 23. Water-dilutable adhesives containing aqueous dispersions after Claim 1.